Core D will support the establishment and maintenance of the COBRE Epithelial Electrophysiology Core facility. The Core will provide the instrumentation, expertise, training and mentoring in epithelial electrophysiology necessary for the advancement of COBRE projects on different epithelia including Project 1: "Transepithelial ion transport and its regulation" (renal collecting ducts and vas deference) and Project 2: "Intestinal epithelial migration: NSAID, polyamine-depletion, and depolarized membrane potential" (equine intestinal epithelia). These projects depend critically on making non-invasive current and non-radioactive ion flux measurements. Based on our expertise and experience and with the goal to advance the mentored projects, we have identified the following equipment for this facility. 1) vibrating current-density probe, 2) self-referencing ion-selective electrodes and 3) scanning conductance probe. This instrumentation in conjunction with the provided expertise, training and mentoring will enable COBRE investigators to establish themselves through advancing their research on epithelia in health and disease.